For magnetic recording/reproducing devices, a coated magnetic tape have been widely used, in which a substrate is coated with a magnetic layer containing lubricant and an abrasive together with a binder.
In a magnetic recording/reproduction device that uses a coated magnetic tape, the lubricant contained in the binder maintains lubricity between the surface of a magnetic head and the magnetic tape, and protects a magnetic film. In the magnetic recording/reproduction device of this type, however, there is a disadvantage that debris of the binder is generated by sliding of the magnetic tape over the magnetic head of the magnetic recording/reproduction device since the binder is contained in the magnetic tape. Consequently, dirt including debris of the binder becomes likely to stick to the magnetic head after a long time use of the magnetic recording/reproduction device, and the magnetic head needs to be cleaned to remove the dirt as appropriate. For example, Patent documents 1 and 2 disclose arrangements in which lubricant is added to a cleaning agent and the lubricant is supplied to the magnetic head together with the cleaning agent during cleaning of the magnetic head.
Patent document 1 discloses an arrangement in which a tank containing a cleaning agent that contains lubricant is provided in a cleaning cassette housing. The tank rotates contacting with a magnetic tape to supply the cleaning agent containing the lubricant to the magnetic tape. Patent document 2 proposes an arrangement in which a soft material impregnated with lubricant is used as a head cleaner, and when cleaning the magnetic head while the magnetic recording/reproduction device is not recording or reproducing, the soft material is switched and contacts with the magnetic head to supply the lubricant to a sliding portion of the magnetic head. The magnetic layer of the coated magnetic tape contains lubricant and the lubricant is supplied unless the magnetic layer has worn away. Therefore there is no great necessity to supply lubricant in addition to the lubricant contained in the magnetic tape.
Since the magnetic layer of the coated magnetic tape contains a binder, which is nonmagnetic material, improvement of the filing density of magnetic material is unfortunately limited by the binder and therefore it is difficult to increase the recording capacities of the coated magnetic tapes.
A magnetic tape which can be overcoming the drawback of the difficulty in increasing the recording capacity of the coated magnetic tape and achieving higher density magnetic recording has been proposed. The magnetic tape, called metal-thin-film magnetic tape, has a recording/reproduction surface that contains no binder. The magnetic tape has a nonmagnetic substrate made of a nonmagnetic material, such as polyester, polyamide or polyimide film, coated with a metal magnetic material such as a Co—Ni alloy, Co—Cr alloy, or Co—O alloy by using a thin-film formation technique such as metal plating, vacuum deposition, sputtering or ion plating.
This type of metal-thin-film magnetic tape has good magnetic characteristics such as coercivity and squareness ratio and its magnetic layer can be formed very thin. Accordingly, the metal-thin-film magnetic tape of this type has good electromagnetic conversion characteristics in a short-wavelength region and has remarkably low demagnetization during recording, and low thickness loss during reproduction. In addition, unlike the coated magnetic tape described previously, the magnetic layer of the metal-thin-film magnetic tape does not contain a nonmagnetic binder. Because of the absence of the nonmagnetic binder, the metal-thin-film magnetic tape has the advantage that the filling density of ferromagnetic metal particles (that is, the magnetic recording density) can be improved to increase the recording capacity, and various other advantages. Therefore, the metal-thin-film magnetic tapes are especially suitable for use as recording media that require huge recording capacities, such as recording media for magnetic recording/reproduction devices for data backup for servers.
Since the metal-thin-film magnetic tape contains no binder in its recording/production surface and it is difficult to contain lubricant and an abrasive in the magnetic layer of the metal-thin-film magnetic tape, the metal-thin-film magnetic tape includes a very thin protective layer on the magnetic layer and a very thin lubricant coat on the protective layer to provide lubricity. Since the recording/reproduction surface contains no binder, the metal-thin-film magnetic tape is less prone to dirt and therefore rarely needs cleaning, unlike the coated magnetic tape.